Certain marine structures such as oil booms, security barriers, floating and submerged nets, floating breakwaters, marina pontoons, and other floating structures need to be repeatedly moved from one position to another. An example is a gate for a fully enclosed military port or harbor, which must be moved from an open position to a closed position and back again.
Current practice for moving booms, barrier gates, etc. is to make connections at the ends of unit structures, or at the ends of a series of end-to-end linked unit structures. Using these conventional techniques, the structure forms a catenary shape as the forces of wind and current push the floating links into a curved condition, as the ends are the only restraints to these forces. In practice, the connections at these ends carry the forces needed to pull the entire structure taut from end to end, while the forces of current, wind and waves can be broadside to the structure. This can result in a substantial force making closure difficult and requiring latching systems to carry both the forces of loads from wind and waves on the structure, as well as operational forces of fluid drag and moving the mass of the marine structure itself.
Another disadvantage of current techniques for moving marine gates or booms is that they require vessels and personnel to physically do the work of moving the structures, and of latching or connecting the ends of the linked structures to their fixed locations. Those vessels and personnel can mishandle the transit, wandering into navigation channels and sometimes causing marine barriers to flip over. The result is high labor and equipment costs, and the danger of injury to personnel.
Hence a need exists for a safer, less costly, and more reliable way of repeatedly moving floating and submerged marine structures.